Jake Wallis Simons finds out what goes into making a royal Easter egg at Nick Crean's London factory.

In an idle moment, have you ever wondered about the provenance of the royal Easter egg? Does the Queen dispatch a courtier to the local shop? Does she order it online? Does the Prince of Wales have seven lined up before him?

Wonder no further: the mystery is solved. Every year, Queen Elizabeth has hers made by Nick Crean, the Royal Warrant holder for fine chocolates. “I write to Buckingham Palace,” he says, “and ask to lay an egg before Her Majesty. She always graciously accepts.”

It takes four hours to make the Royal egg, which weighs 4lbs and is stuffed with a variety of goodies.

At Crean’s factory in north London, Gabi Kohler, the head chocolatier, shows me how it is done. “We use 71 per cent cocoa chocolate,” she says, “but you can use whatever you like. You can mix white and dark for a marbled effect.”

At home, it is best to melt the chocolate in a bowl over a pan of hot water. It should be no hotter than 42C/ 108F, to prevent it becoming grainy and discoloured. Either use a cooking thermometer, or dip your finger in to check that the chocolate is warm – but not hot – to the touch.

Gabi pours the chocolate into two half-egg moulds with an antique porcelain jug, which is only ever used for the Queen. Then they are swirled until the chocolate coats the entire inner surface. The excess chocolate is poured back into the pan – it is important not to allow the chocolate to pool in the centre, as this will create a thick middle and fragile edges – and the moulds are placed in the fridge. After five minutes, when the chocolate has started to harden, any crusts of chocolate are trimmed with a knife. Then the moulds are refrigerated until the chocolate is set.

Royal flourish: only the Queen’s egg is poured from an antique jug and contains a white rabbit (Pic: Andrew Crowley)

Using transparent moulds is important. “When you pour the chocolate in, the outside of the mould turns dark brown,” says Gabi. “When the chocolate has hardened and shrunk away from the plastic, the darkness fades. That means it’s ready.” Once the first layer is set, further layers can be added to increase the thickness. Removing the egg is simple: it just clicks out.

The two halves are wrapped in foil, tied with a ribbon and presented to the Queen in a pink box filled with tissue paper. First, however, they are filled with goodies: champagne truffles, mini Easter eggs and bars. There is also a white chocolate rabbit, which is only ever placed in the Royal egg.

“At home, I would suggest filling it with home-made truffles,” says Gabi. To demonstrate, she melts chopped chocolate, mixes it with cream, sugar and butter, and chills it to create a ganache. Then, using a piping bag, she squeezes blobs onto a sheet of baking paper. These are then rolled in icing sugar.

The finished truffles can be hidden in the egg for an Easter surprise. If it’s good enough for the Queen…